Spark arrester for internal combustion engines



J .3. 1931. F. A. DQNALDSON 1,811,043

SPARK ARRESTER FOR INTERNAL COMBUSTION ENGINES Filed Feb. 21. 1929 Patented June 23, 1931 FRANK A. NONALCDSON, OF ST. PAUL, MINNESOTA SPARK ARBESTER FOR INTERNAL COMBUSTION ENGINES Application filed February 21, 1929. Serial No. 341,675.

This invention relates to spark arresters for internal combustion engines and is in the nature of a modification of the spark arrester disclosed-and claimed in my United States application, executed of even date herewith entitled Spark arrester for internal combustion engines, Serial Number 341,674, filed February 21, 1929.

In the accompanying drawings, like characters indicate like parts throughout the several views.

Referring to the drawings: 7 Fig. 1 is an axial sectional view of the arrester; and v Fig. 2 is a section taken on the line 22 of Fig. 1.

The numeral 3 indicates a tubular sheet 'metal casing, which casing comprises the main body of the arrester and which is provided at its intake end with a head 4 and at its outlet end with a head 5. These heads 4 and 5 are illustrated as being secured to their respective ends of the casing by means of flange and rolled-edge connections 6.

The head 4 at the intake end of the arrester is provided with an axial internally threaded sleeve 7 that is illustrated ashaving screw threaded engagement with an eX- haust pipe 8, which pipe may be assumedto lead to the exhaust manifold of an internal combustion engine not shown. The head 5 at the outlet end of the arrester is punched out at its center to'form an axial outlet op- 'ening 9 projecting outward from the edge of which is an annular collar 10. Extending inward fromthe outlet opening 9 to the interior casing is an outlet tube 11, the

outer edge portion of which fits within the annular collar 10 and is suitably secured thereto by welding or the like at 12.

WVit-hin the tubular casing 3 is a series of axially spaced baffle partitions. The bafile partitions near the intake end of the casing is indicated by the numeral 120), the inter.- a mediate partition by the numeral 18, and the partition near the outlet end of the arrester by the numeral 14. These bafi le partitions 120;, 13, and 14 divide the interior of the casing into several compartments, to wit: a compartment 16 at the intake end of the cas-.

ing, a compartment 17 at the outlet end of the casing and intermediate compartments 18. In the baffle partitions 12a, 13 and 14 near the outer edge portions of each thereof is formed an annular series of circumferentially spaced deflecting blades or veins 15 for successively imparting a whirling motion to spark laden gases passed through the intenor of the casing.

it should now be noted that the baffle partltion 12a near the intake end of the arrester is closed at its central portion inside of the annular series of deflecting blades formed near the outer portion thereof, and that the intermediate baffle partition 13 and the b'aflle' partition 14 near the outlet end of the arrester are provided with axial outlet openmgs 1400. It will further be noted that the outlet tube 11 extends close to the baffle blades in the last partition near the outlet' end of the arrester and that the diameter of the'outlet tube 11 is preferably not greater than the distance between the inside portions of circumferentially spaced blades 15 in the partition 14.

All of the spark laden gases delivered into the compartment l6 at'the intake end of the casing from the exhaust pipe 8 will, of course, becaused to pass through the oblique deflecting blades in the baflie partition 12a, and will be caused to whirl at relatively high velocity upon entering thefirst intermediate compartment 18. The sparks thus bemg whirled at high velocity will be thrown outward by centrifugal force,-andwill travel close to the sides of the casing.

By throwing the heavier than air particles, such as hot sparks of carbon, toward the side of the casing in the intermediate compartment, it will be apparent thatthe v gases near the axis of the casing will be clean and free from sparks or the like. These clean. gases, near the axis of the easing in the first intermediate compartment will be passed uninterruptedly into the-second compartment through the axial opening in the intermediate bafiiing partition 13,

and the spark laden gases near the sides of the casing will pass into the second inter mediate compartment through the deflecting blades 18, in said baflle partitions 13. The spark laden gases thus passed through the second intermediate compartment will by the action of the last noted deflecting blades be stepped up in their whirling motion thus keeping all the sparks close to the side of the casing.

The clean gases near the axis of the second intermediate compartment will pass directly through the axial opening 14a in the deflecting partition 14 near the outlet end of the arrester to the aligned outlet tube 11 and therethrough to the open atmosphere, and spark laden gases near the side of the casing will pass through the deflecting blades in the baffle partition 14 to the compartment 17 at the outlet end of the arrester and will again be stepped up in their whirling motion. The sparks thus passed into the compartment 17 will be thrown outward and toward the outlet end of the casing and will whirl around in the space between the outlet tube 11, and the sides of the casing until they become spent, and the gases passed into the outside portion of the compartment 17 will reverse their course of travel and pass through the open inner end of said outlet tube 11 to the atmosphere with the other cleaned gases.

It should however be understood that a large percentage of the sparks entering the inlet end of the arrester will, due to their long course of travel caused by the whirling motion imparted thereto by the several series of deflecting blades, become entirely spent in the compartments preceding the compartment 17 at the outlet end of the arrester and therefore those sparks entering said compartment 17 will in most cases have become so reduced in size that they will quite readily become entirely spent. The compartment 17 having the outlet tube extended therein as illustrated may be considered a spark trap.

The arrester is illustrated as being employed in a vertical position but may be employed efficiently in a horizontal position.

When a device isused in a vertical position, however, rain water may come through the outlet tube 11 when the arrester is inoperative. This water will drop through the several baffle partitions and on to the head at the intake end of the arrester, and through small drain holes 19 therein. The water will not be allowed to drop into the exhaust pipe 8 for the reasons that the central portion of the partition 12a directly above the open end of the exhaust pipe is closed so that the water will be caused to drop through the blades 15 in the partition 12a and on to the head 4: outside of the open end of the exhaust pipe where it will be re-.

tained by the inwardly projecting sleeve 7 until it has drained out through the holes 19.

What I claim is:

l. A spark arrester comprising a tubular casing having a head at each end thereof, an intake passage near one end of the casing and an axial other passage in the head at the outlet end of the arrester, axially spaced partitions in said casing, an annular series of circumferentialy spaced deflecting blades or veins formed near the outer edge of each of said partitions close to the side of the casing, the baffle partition near the intake end of the arrester having a closed central por tion and the partition near the outlet end of the arrester having an axial opening, and an outlet tube extending inward from the axial outlet passage in the head at the outlet end of the arrester and terminating short of the partition at the outlet end of the arrester.

2. A structure defined in claim 1 in which the open inner end of the outlet tube is of' greater diameter than the axial opening in the baflle partition at that end of the arrester, but of less diameter than the distance between the inner edge portions of diametrically opposed blades in said partition.

3. A spark arrester comprising a tubular casing having a head at each end thereof, an axial inlet in the head at one end of the arrester and an axial outlet in the head at the other end of the arrester, a series of battle partitions in the casing that are spaced axially from one another and from said casing heads to form end compartments and intermediate compartments, an annular series of circumferentially spaced deflectors near the outer portion of each of said bafile partitions, the partition near the'intake end of the arrester being closed at its central portion and the intermediate partition and the partition at the outlet end of the arrester having an axial opening and an outlet tube extending inwardly from the axial outlet into the compartment at the outlet end of the arroster and terminating short of the partition at the outlet end of the arrester and spaced from the sides of the casing slightly more than the distance between the casing and the inside of the deflectors.

4. A spark arrester comprising a tubular casing having an inlet in one end thereof and an axial outlet near the other end thereof, an axially spaced series of battle partitions in said casing and an annular circumferentially spaced series of deflecting blades or veins in each of said baffle partitions near the outer edge portions thereof, the first baffle partition at the intake end of the arrester being closed to incoming gases at its central portion so that all of the incoming spark-laden gases will be passed through the first set of blades or veins and have a whirling motion imparted thereto, thereby causing heavier than air particles therein to be thrown outward by centrifugal force and follow close to the sides of the casing, and an axial opening through each of the following bafiies for permitting spark free gases near the axis of the casing to be passed to the outlet without having further whirling motion 7 imparted thereto.

In testimony whereof I afiix my signature.

FRANK A. DONALDSON. V 

